Penning trap mass spectrometry of neutron-rich Fe and Co isotopes around N = 40 with the LEBIT mass spectrometer

• Published in: Physical review. C, Nuclear physics Nuclear physics, 2010-04, Vol.81 (4), Article 044318
• Main Authors: Ferrer, R., Block, M., Bachelet, C., Barquest, B. R., Bollen, G., Campbell, C. M., Facina, M., Folden, C. M., Guénaut, C., Kwiatkowski, A. A., Lincoln, D. L., Morrissey, D. J., Pang, G. K., Prinke, A. M., Ringle, R., Savory, J., Schury, P., Schwarz, S.
• Format: Article
• Language: English
• Subjects: ACCURACY; BARYONS; BEAMS; BETA DECAY RADIOISOTOPES; BETA-MINUS DECAY RADIOISOTOPES; BINDING ENERGY; CHARGED PARTICLES; CLOSURES; COBALT 64; COBALT 65; COBALT 66; COBALT 67; COBALT ISOTOPES; DECAY; DEFORMATION; ELEMENTARY PARTICLES; ENERGY; EVEN-EVEN NUCLEI; EVEN-ODD NUCLEI; FERMIONS; FORECASTING; HADRONS; INTERMEDIATE MASS NUCLEI; IONS; IRON 63; IRON 64; IRON 65; IRON 66; IRON ISOTOPES; ISOMERS; ISOTOPES; MASS; MASS SPECTROMETERS; MASS SPECTROSCOPY; MEASURING INSTRUMENTS; MILLISECONDS LIVING RADIOISOTOPES; NEUTRON SEPARATION ENERGY; NEUTRON-RICH ISOTOPES; NEUTRONS; NUCLEAR DECAY; NUCLEAR DEFORMATION; NUCLEAR PHYSICS AND RADIATION PHYSICS; NUCLEAR STRUCTURE; NUCLEI; NUCLEONS; ODD-EVEN NUCLEI; ODD-ODD NUCLEI; RADIOISOTOPES; SECONDS LIVING RADIOISOTOPES; SPECTROMETERS; SPECTROSCOPY; TRAPS
• ISSN: 0556-2813; 1089-490X
• DOI: 10.1103/PhysRevC.81.044318

Penning trap mass spectrometry is presented as a complementary tool to nuclear spectroscopy experiments for the study of nuclear structure in the vicinity of N=40, Z=28. High-precision mass measurements of the {sup 63-66}Fe and {sup 64-67}Co isotopes have been carried out with the Low Energy Beam and Ion Trap (LEBIT) Penning trap mass spectrometer. The newly obtained mass values for {sup 66}Fe and {sup 67}Co are presented, together with the previously reported LEBIT mass measurements in this region. In the case of {sup 65}Fe the existence of a new isomer is reported, and an isomer recently discovered by decay spectroscopy in {sup 67}Co is confirmed. Relative mass uncertainties as low as 4x10{sup -8} are obtained. All mass values are found to be in good agreement with previous experimental results with the exception of {sup 64}Co, where a 5sigma deviation is observed. Using these data the two neutron separation energies S{sub 2n} are calculated. However, the large error bars in the mass values of the neighbor Fe and Co isotopes with N>40 complicate the validation of a weak subshell closure at N=40 for the Co isotopes or the possible reduction in the neutron shell gap in the case of the Fe isotopes, in accordance with the theoretical predictions of an onset of deformation in the region.